Verbunddübelleisten bieten im Brückenbau ein breites Einsatzspektrum. Sie sind einfach herzustellen und stellen bei der Übertragung der Schubkräfte in der Verbundfuge eine dauerhafte und robuste Lösung dar. Aus der neuartigen Wirkungsweise ergeben sich neue Konstruktionen im Verbundbrückenbau. Der Aufsatz gibt einen Überblick über Konstruktion und Wirtschaftlichkeit ausgeführter Bauwerke mit Verbunddübelleisten.Economic composite constructions for bridges ‐ Construction methods implementing composite dowel strips. Composite dowel strips find a wide range of application in bridges. They are easy to manufacture and the transmission of shear forces of the composite action is long lasting and robust. Beside the innovative composite action new construction methods for composite bridges are established. The article summarizes already executed bridge structures implementing composite dowel strips due to construction details and economic aspects.

The bridges are vital structures for the transport infrastructure; it is a fact that, in the last decades, composite bridges became a well-liked solution in many European countries as a cost-effective and aesthetic alternative to concrete bridges. Their competitiveness depends on several circumstances such as site conditions, local costs of material and staff and the contractors experience. Beside the classical solution, the new ones with efficient design and construction improve and consolidate the market position of the steel construction and steel producing industry. These bridge solutions combine many important aspects: reduced costs, fast and simple erection, durability and robustness, low maintenance costs and an appealing aesthetical aspect. Another feature is the robustness of composite bridges. The robustness of a structure has to be defined as being the capacity of the system to keep its structural integrity for any kind of action that may occur during its service life. The present tendency in composite bridges consists in simplifying the structure as much as possible. Continuous shear connection using a cut steel strip is a solution for composite beams. With the introduction of the composite dowel the possibility is given to develop new construction methods for bridges. The paper will include interesting aspects regarding the dimensioning of the structure and technological features and also aspects related to the efficiency, robustness and fatigue behavior of the joints with composite dowels in bridges. The behavior of the dowels has a theoretical background based on laboratory investigations. The Romanian railway and highway infrastructure is presently involved in a large operation of renewal and modernization. The solution was recently introduced in Romania for three highway bridges of medium spans.

Integral abutment bridges are becoming popular in Europe, mainly due to long term reduced maintenance costs. The lack of bearings and expansion joints means that the consumables are eliminated ensuring a longer life span of the structure and minimizing the need of human intervention. Most integral bridges usually have small or middle lengths, but in the last years longer bridges are being built. Special attention should be given to the soil-abutment interaction, as the bridge lengthens and shortens during the day and during the year, due to temperature differences and loading. Therefore the soil structure should accommodate the cyclic movements of the abutment and avoid settlements and cracks. Transition slabs are also key elements and targeted design can improve the behavior of the bridge. In the past years several integral bridges were built in Romania. The paper presents examples with bridges from the Romanian Motorway system, addressing the specific needs and adopted solutions in regard to their lengths.

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FachthemenDer Aufsatz beschreibt den Stand der Kenntnisse bei der Bestimmung der Tragfähigkeit, der Ermüdung und der Ertüchtigung bestehender Stahlbrücken in Rumänien. Die Autoren stellen die rumänischen Normen im Bereich stählerner Eisenbahn-und Straßenbrücken vor und empfehlen Ertüchtigungsmethoden. Aufgrund neuer bruchmechanischer Untersuchungen an alten Stahlbrücken schlagen die Autoren neben den klassischen Verfahren der Schadensakkumulation die komplementäre bruchmechanische Methode vor.Determination of design resistance of existing steel bridges in Romania. The paper describes the state of the art in determination of design resistance, fatigue and rehabilitation of existing steel bridges in Romania. The authors present the Romanian codes for steel bridges of railways and roadways and propose methods of rehabilitation. Because of recent research in fracture mechanics applied to old steel bridges, the authors propose the classic method of damage accumulation along with the complementary method based on the fracture mechanics method. 606